Hello Stacie
There are many UK Susan's members with GenderGP of which I am one and there are also several GenderGP threads either on Transgender Talk Board or here on HRT Board.
I applied to GenderGP last year and am very pleased with their all round service.
At first you will be asked questions mainly medical but also you initial thoughts and aims. If you decide to join and pay initial sum, you will be granted therapy either by phone or Skype or attendance, at an extra cost per session but often only 1 or 2 is/are necessary before HRT by Informed Consent (provided therapist and you desire it) is granted and initially you pay prescription and monthly charge to GenderGP. If you wish to continue with HRT after say 3 months, GenderGP may arrange a "Shared Care Agreement" between GenderGP and your NHSGP and in that event, you then only pay monthly charge to the former and your NHS prescriptions are under the NHS system.
I wish you well if you decide to use them for therapy and/or HRT. I am well pleased with their efficiency, understanding and general transgender care.
Hugs
Pamela